Prenatal exposure to prescription drugs has been linked to teratogenicity and chronic diseases of the offspring in the later life. While many pregnant women take prescription drugs, the safety of most drugs during pregnancy is not well understood. Commonly used data sources and designs for safety studies in pregnant women have several limitations including recall bias of drug exposure (case-control studies), and small size to detect rare adverse events (cohort studies). These data sources are also expensive to generate, and are often limited to a few pre-specified outcomes assessed shortly after birth. Although, large health care utilization databases have become the standard source of information for pharmacoepidemiologic studies on the safety of drugs, few studies used these data sources in studying the safety of drugs during pregnancy. We have identified administrative data with pharmacy dispensing from the entire province of British Columbia that are further linkable to clinical information on birth and reproductive history. These population-based health care utilization data with linkable birth data have the potential to enhance the research of drug utilization and safety during pregnancy. We propose to develop a research database that identifies pregnant women and their offspring to study drug utilization and safety of prescription drugs in pregnant women. To test the validity and usefulness of the new research database, we will assess the association between selective serotonin reuptake inhibitor use during pregnancy and clinical outcomes in the offspring, including persistent pulmonary hypertension of the newborns (PPHN), and cardiovascular defects. To enhance the validity of the research database, we will further assess the accuracy of coded diagnosis of PPHN and cardiovascular defects and develop the most specific algorithm to define these outcomes. Upon completion of this study (R21), we will have developed the research database and tested relevant hypotheses that will help inform the usefulness and validity of the database in studying drug safety during pregnancy. Project Narrative: We will develop and test the utility of a research database that identifies pregnant women and their children using population-based claims databases to study safety of prescribed drugs during pregnancy. This database based on large population-based follow-up data with linkable clinical birth data has the potential to enhance the safety of prescription drug use in pregnant women and their children. [unreadable] [unreadable] [unreadable]